solid waste management

1. Solid Waste
Management

10. History
In ancient cities, food scraps and other wastes
were simply thrown into the unpaved streets
where they accumulated.
Around 320 B.C. in Athens, the first known law
forbidding this practice was established and a
system of waste removal began to evolve in
several eastern Mediterranean cities.

11. Around most towns and cities in India
the approach roads are littered with
multi-coloured plastic bags and other
garbage.

12. Waste is also
burnt to reduce its volume.

13. Lack of space for dumping solid waste has become
a serious problem in several cities and towns all
over the world.
Dumping and burning wastes is not an acceptable
practice today from either an environmental or a
health perspective.
The method of collection, processing, resource
recovery and the final disposal should mesh with
one another to achieve a common objective.

14. municipal solid waste (MSW)
It is generally used to describe most of the non-
hazardous solid waste from a city, town or
village that requires routine collection and
transport to a processing or disposal site.
Sources of MSW include private homes,
commercial establishments and institutions as
well as industrial facilities.

15. However MSW does not include
wastes from
• Industrial processes
• Construction and demolition debris
• Sewage sludge
• Mining wastes or
• Agricultural wastes.

16. Municipal solid waste contains food
waste such as
• Vegetable
• Meat Material
• Left Over Food
• Egg Shells, Etc
which is classified as wet garbage

17. Municipal solid waste contains
• Paper
• Plastic
• Tetrapacks
• Plastic Cans
• Newspaper
• Glass Bottles
• Cardboard Boxes
• Aluminum Foil
• Metal Items
• Wood Pieces, Etc.
Which is classified as dry garbage.

18. CONTROL MEASURES OF URBAN
AND INDUSTRIAL WASTES:

19. Waste as renewable energy

20. An integrated waste management
strategy includes three main
components:
1. Source reduction
2. Recycling
3. Disposal

21. Source reduction
Source reduction is one of the fundamental ways to
reduce waste. This can be done by using less
material when making a product, reuse of products
on site, designing products or packaging to reduce
their quantity.
On an individual level we can reduce the use of
unnecessary items while shopping, buy items with
minimal packaging, avoid buying disposable items
and also avoid asking for plastic carry bags.

22. RECYCLING

23. Recycling of plastic

24. Plastic road

25. Recycling
Recycling is reusing some components of the
waste that may have some economic value.
Recycling has readily visible benefits such as
conservation of resources reduction in energy
used during manufacture and reducing pollution
levels.
Some materials such as aluminum and steel can
be recycled many times.
Metal, paper, glass and plastics are recyclable.

26. Mining of new aluminum is expensive
and hence recycled aluminum has a
strong market and plays a significant
role in the aluminum industry.

27. Paper recycling can also help preserve
forests as it takes about 17 trees to
make one ton of paper.

28. Crushed glass (cullet) reduces the energy
required to manufacture new glass by 50
percent. Cullet lowers the temperature
requirement of the glassmaking process thus
conserving energy and reducing air pollution.
However even if recycling is a viable alternative,
it presents several problems.

29. Plastics
The problems associated with recycling are
either technical or economical. Plastics are
difficult to recycle because of the different types
of polymer resins used in their production.
Since each type has its own chemical makeup
different plastics cannot be recycled together.
Thus separation of different plastics before
recycling is necessary.

30. Paper
Similarly in recycled paper the fibers are
weakened and it is difficult to control the colour
of the recycled product.
Recycled paper is banned for use in food
containers to prevent the possibility of
contamination.
It very often costs less to transport raw paper
pulp than scrap paper.

31. Collection, sorting and transport account for about
90 percent of the cost of paper recycling.
The processes of pulping, deinking and screening
wastepaper are generally more expensive than
making paper from virgin wood or cellulose fibers.
Very often thus recycled paper is more expensive
than virgin paper.
However as technology improves the cost will come
down.

32. Disposal
Disposal of solid waste is done most commonly
through a sanitary landfill or through
incineration.
A modern sanitary landfill is a depression in an
impermeable soil layer that is lined with an
impermeable membrane.
The three key characteristics of a municipal
sanitary landfill that distinguish it from an open
dump are:

33. • Solid waste is placed in a suitably selected and
prepared landfill site in a carefully prescribed
manner.
• The waste material is spread out and
compacted with appropriate heavy machinery.
• The waste is covered each day with a layer of
compacted soil.

34. The problem with older landfills are associated with
groundwater pollution.
Pollutants seeping out from the bottom of a
sanitary landfill (leachates) very often percolate
down to the groundwater aquifer no matter how
thick the underlying soil layer.
Today it is essential to have suitable bottom liners
and leachate collection systems along with the
installation of monitoring systems to detect
groundwater pollution.

35. The organic material in the buried solid waste will
decompose due to the action of microorganisms.
At first the waste decomposes aerobically until the
oxygen that was present in the freshly placed fill is
used up by the aerobic microorganisms.
The anerobes take over producing methane which
is poisonous and highly explosive when mixed with
air in concentrations between 5 and 15 percent.

36. The movement of gas can be controlled by
providing impermeable barriers in the landfill.
A venting system to collect the blocked gas and
vent it to the surface
where it can be safely diluted and dispersed into
the atmosphere is thus a necessary component
of the design of sanitary landfills.

37. Even though landfilling is an economic alternative
for solid waste disposal, it has become increasingly
difficult to find suitable landfilling sites that are
within economic hauling distance and very often
citizens do not want landfills in their vicinity.
Another reason is that no matter how well
engineered the design and operation may be, there
is always the danger of some environmental
damage in the form of leakage of leachates.

38. Incineration is the process of burning municipal solid
waste in a properly designed furnace under suitable
temperature and operating conditions.
Incineration is a chemical process in which the
combustible portion of the waste is combined with
oxygen forming carbon dioxide and water, which are
released into the atmosphere. This chemical reaction
called oxidation results in the release of heat.
For complete oxidation the waste must be mixed with
appropriate volumes of air at a temperature of about
815o C for about one hour.

39. Incineration can reduce the municipal solid
waste by about 90 percent in volume and 75
percent in weight.
The risks of incineration however involve air
quality problems and toxicity and disposal of the
fly and bottom ash produced during the
incineration process. Fly ash consists of finely
divided particulate matter, including cinders,
mineral dust and soot.

40. Most of the incinerator ash is bottom ash while the
remainder is fly ash. The possible presence of heavy
metals in incinerator ash can be harmful. Thus toxic
products and materials containing heavy metals (for
example batteries and plastics) should be segregated.
Thus extensive air pollution control equipment and high-
level technical supervision and skilled employees for
proper operation and maintenance is required.
Thus while sanitary landfills and incinerators have their
own advantages and disadvantages, the most effective
method of solid waste management is source reduction
and recycling.

41. Vermi – Composting
Nature has perfect solutions for managing the
waste it creates, if left undisturbed.
The biogeochemical cycles are designed to clear the
waste material produced by animals and plants.
We can mimic the same methods that are present
in nature.
All dead and dry leaves and twigs decompose and
are broken down by organisms such as worms and
insects, and is finally broken down by bacteria and
fungi, to form a dark rich soil-like material called
compost.

42. These organisms in the soil use the organic
material as food, which provides them with
nutrients for their growth and activities.
These nutrients are returned to the soil to be
used again by trees and other plants. This
process recycles nutrients in nature.
This soil can be used as a manure for farms and
gardens.

43. Vermi compost

44. Steps for Vermi-Compost
Dig a pit about half a meter square, one
meter deep.
Line it with straw or dried leaves and grass.
Organize the disposal of organic waste into
the pit as and when generated.
Introduce a culture of worms that is now
produced commercially.

45. Steps for Vermi-Compost
Ensure that the contents are covered with a
sprinkling of dried leaves and soil everyday.
Water the pit once or twice a week to keep it
moist.
Turn over the contents of the pit ever 15 days.
In about 45 days the waste will be decomposed
by the action of the microorganisms.
The soil derived is fertile and rich in nutrients.

46. Hazardous waste
A waste is classified as a hazardous waste if
it exhibits any of the four primary
characteristics based on the physical or
chemical properties of toxicity, reactivity,
ignitability and corrosive.
In addition to this waste products that are
either infectious or radioactive are also
classified as hazardous

47. Toxic wastes
Toxic wastes are those substances that are
poisonous even in very small or trace amounts.
Some may have an acute or immediate effect on
humans or animals causing death or violent
illness.
Others may have a chronic or long term effect
slowly causing irreparable harm to exposed
persons.

48. Acute toxicity is readily apparent because
organisms respond to the toxin shortly after being
exposed.
Chronic toxicity is much more difficult to determine
because the effects may not be seen for years.
Certain toxic wastes are known to be carcinogenic,
causing cancer and others may be mutagenic
causing biological changes in the children of
exposed people and animals.

49. Reactive wastes are those that have a
tendency to react vigorously with air
or water, are unstable to shock or
heat, generate toxic gases or explode
during routine management.
For example, gunpowder,
nitroglycerine, etc.

50. Ignitable wastes are those that burn at
relatively
low temperatures (less than 60 C) and
are capable of spontaneous
combustion during storage, transport
or disposal.
For example, gasoline, paint thinners,
and alcohol.

51. Corrosive wastes are those that destroy materials
and living tissue by chemical reaction. For example,
acids and bases.
Infectious wastes include human tissue from
surgery, used bandages and hypodermic needles,
microbiological materials, etc.
Radioactive waste is basically an output from the
nuclear power plants and can persist in the
environment for thousands of years before it decays
appreciably.